Which one of the following show origin and evolution of steles

Options

A. Bryophytes
B. Pteridophytes
C. Gymnosperms
D. Angiosperms

Answer

**Step-by-Step Solution:**

1. **Understanding Steles**:
- Steles are defined as the central cylinder or core of vascular tissue in higher plants. They consist mainly of xylem and phloem, which are essential for water and nutrient transport.

2. **Classification of Plant Kingdom**:
- The plant kingdom is classified into five major groups: algae, bryophytes, pteridophytes, gymnosperms, and angiosperms. Each of these groups represents different levels of vascular development.

3. **Historical Context**:
- The concept of steles was introduced by Van Teghem and Doliot in 1886. They proposed the "steel theory" or "stellar theory," which explains the evolution of vascular systems in plants.

4. **Evolution of Steles**:
- According to the steel theory, the advanced vascular systems of higher plants (pteridophytes, gymnosperms, and angiosperms) led to the development of steles. This indicates that steles evolved as plants became more complex.

5. **Origin of Steles**:
- The origin of steles is traced back to pteridophytes. This group of plants represents the first significant development of a vascular system that includes steles.

6. **Conclusion**:
- Therefore, the answer to the question is that pteridophytes show the origin and evolution of steles.

**Final Answer**: Pteridophytes show the origin and evolution of steles.

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